# HG changeset patch
# User Michael Pavone <pavone@retrodev.com>
# Date 1446693279 28800
# Node ID adeb6465ad53b6abbe80be5306062e2f59f518f8
# Parent  2d474efb4629c1846357c25b4065b923c7608559
Improve timing of Z80 busack. Fixes a crash in Barkley: Shut Up and Jam. Also vastly improves the audio output of Stuck Somewhere in Time

diff -r 2d474efb4629 -r adeb6465ad53 z80_to_x86.c
--- a/z80_to_x86.c	Tue Nov 03 07:41:10 2015 -0800
+++ b/z80_to_x86.c	Wed Nov 04 19:14:39 2015 -0800
@@ -14,6 +14,7 @@
 #include <string.h>
 
 #define MODE_UNUSED (MODE_IMMED-1)
+#define MAX_MCYCLE_LENGTH 6
 
 //#define DO_DEBUG_PRINT
 
@@ -2623,6 +2624,11 @@
 {
 	z80_run(context, cycle);
 	context->busreq = 1;
+	//this is an imperfect aproximation since most M-cycles take less tstates than the max
+	//and a short 3-tstate m-cycle can take an unbounded number due to wait states
+	if (context->current_cycle - cycle > MAX_MCYCLE_LENGTH * context->options->gen.clock_divider) {
+		context->busack = 1;
+	}
 }
 
 void z80_clear_busreq(z80_context * context, uint32_t cycle)